Apparatus for casting articles in permanent metal molds



Jan. .23, E945. H. E. MCWANE APPARATUS FOR CASTING ARTICLES IN PERMANENTMETAL MOLDS Filed Dec. 15, 1941 6 Sheets-Sheet 1 M 49, awzqgw Wag v Jan.23, 1945. H. E. McWANE APPARATUS FOR CASTING ARTICLES IN PERMANENT METALMOLDS Filed Dec. 13, 1941 6 Sheets-Sheet 2 Jim, 1945- H. E. McWANE2,367,727

APPARATUS FOR CASTING ARTICLES IN PERMANENT METAL MOLDS Filed Dec. 13,1941 6 Sheets-Sheet 5 jam. 23; 1945. H. E. MCWANE 2,367,727

APPARATUS FOR CASTING ARTICLES IN PERMANENT METAL MOLDS Filed Dec. 15,1941 e Sheets-Sheet 4 v W 45 if ,4 I W W {I (@[iszr 23 Fig-45. McWANE2,367,727

APPARATUS FOR CASTING ARTICLES IN PERMANENT METAL MOLDS Filed Dec. 13,1941 6 Sheets-Sheet 5 APPARATUS FOR CASTING ARTICLES IN PERMANENT METALMOLDS Filed Dec. 15, 1941 e Sheets-Sheet 6 Patented Jan. 23, 1945APPARATUS FOR CASTING ARTICLES IN PERMANENT METAL MOLDS Henry E. Mcwane,Lynchburg, Va.

Application December 13, 1941, Serial No. 422,912

3 Claims.

The present invention relates to the art of casting and moreparticularly to an apparatus for casting articles in permanent metalmolds whereby deleterious strains due to shrinkage of the casting oncooling are eliminated. This case is a continuation in part of myco-pending application, Serial No. 281,973, filed June 29, 1939, andentitled Apparatus and method of casting.

It is, of course, well known that relatively thin articles, such as,plow mold boards and points, cool rapidly after the metal has beenpoured.

' the casting.

These articles are often formed with ribs, flanges,

apertures and the like, and the casting if maintained securely within arigid permanent mold will cause weakened metal, or fractures between theribs, flanges, etc., if the metal shrinks between them. Naturally themold parts must be securely held in close contact with each other as themetal is being poured and while it sets to obtain a good casting.However, if the mold parts are held in the closed position during thecooling cycle of the metal, the. shrinkage of the cooling metal willcause the casting thus held to stretch beyond its elastic limit.

One of the paramount purposes of the present invention is to provide apermanent metal mold, the parts of which may be cracked or moved awayfrom each other a. small distance after the molten material has beenpoured and has set, thereby permitting a free shrinkage of the castingindependently of the mold. Or, to express it in a different manner,there is provided by the present application a method and apparatuswhereby binding of the shrinking metal within the mold is eliminated.

.An important object of the present invention is to accomplish the abovepurpose.

And another object of the present invention is to provide an apparatuswherein a movable mold part is moved into operative position withrespect to a fixed mold part during the pouring cycle,

then moving the movable mold part a suificient distance aftersolidification but before shrinkage of the molten material to permit thematerial to shrink in the mold but not far enough to allow the castingto fall from the mold and finally moving the movable mold partcompletely away from the fixed mold part to enable the .cast article tobe removed.

And another object is to provide a timing cycle for casting in permanentmetal molds whereby the mold is first automatically closed for pouringand is held in the closed position under pressure for a predeterminedperiod whereupon the mold parts are separated slightly for a medetermined period of time to enable the molten material to shrink andlastly the mold parts are completely separated to permit the removal ofYet a further object of the invention is to provide a novel timeoperated valve mechanism for actuating the movement of the movable moldpart with respect to the stationary mold part.

And a further object of the present invention is to provide a plungerconstruction for moving a movable mold part away from a fixed mold partwhich operates in conjunction with a pressure closing means to separatethe mold parts a predetermined distance.

To accomplish the above and other advantageous objects, I employ a fixedmold section and a movable mold section which is adapted to be movedinto operative position with respect to the fixed mold section. Themovable mold part is held against the fixed mold part for apredetermined period of time during the pouring step. The movable moldsection is maintained in this position under pressure until the moltenmaterial has solidified but before it begins to shrink, at which timethe movable mold section is automatically moved a short distance awayfrom the fixed mold section to permit the casting to shrink freelywithin the mold. After the casting has completely cooled, the movablemold section is moved a further distance away from the fixed moldsection thereby permitting the operator to have easy access to the moldfor removing the cast article. A timing device is provided to controlthe cycle of the above functions.

In the drawings in which like numerals designate the same or similarparts:

Figure 1 is a top lan view of a casting machine embodying my inventiveconcept.

Figure 2 is a view in side elevation of the machine illustrated inFigure 1. Figure 3 is a sectional view taken along the line 3-3 ofFigure 2. looking in the direction of the arrows.

Figure 7 is a sectional view taken along the line 1-1 of Figure 2looking in the direction or the arrows.

Figure 8 is a sectional view taken along the line 8-8 of Figure 2looking in the direction of the arrows.

Figure 9 is a conventionalized sectional view of the various mechanismsfor operating the movable mold part.

Figure 10 is a diagrammatic representation 01 the timing mechanism foroperating the casting cycle illustrating the mold parts in the operativeposition.

Figure 11 is a diagrammatic representation of the same parts shown inFigure 10 illustrating their position when the movable mold part is inposition against the fixed mold part for the pouring step.

Figure 12 is a diagrammatic representation of the control cycle showingthe relative position of the elements when the movable mold part ismoved slightly away from the fixed mold part to permit the casting toshrink within the mold.

Figure 13 is a diagrammatic representation of the position of theelements constituting the control means when the movable mold part ismoved completely away from the fixed mold part to permit the castarticle to mold.

Referring to Figure 1, there is shown a casting machine designatedgenerally I which employs a fixed bed plate 2 and a movable bed plate 3.The movable bed plate 3 is adapted to slide toward and away from thefixed bed plate 2 on tracks 4. A guide member is carried by each side ofthe movable bed plate 3 and adjustinggibs 6 are associated therewith forcompensating for wear. One end of each guide rail 4 is secured to thefixed bed plate 2 as shown at I, and a yoke 8 joins the opposite ends ofthe guide rails 4.

The bed plate 2 is hingedly fixed to a support leg 9 as shown at ill toenable the frame i to be moved from the horizontal position illustratedin Figures 1 and 2 to the vertical position shown by the dot dash linesin Figure 5. The yoke 23 is adapted to rest on a support II when theframe is in the horizontal position and attention is called to Figure 2.

Bolted to the fixed bed plate 2 is one half [2 of a water jacketedpermanent metal mold iii. The structure of the mold i3 is shown anddescribed in my co-pending application, Serial No. 413,214, filedOctober 1, 1941. Conduits i l and i5 are in communication with the waterjacket for circulating the necessary cooling medium in the water Jacket.

Secured to the movable bed plate 3 is the opposite half l6 of the moldl3 and when the two halves are in operative position they definetherebetween a casting cavity ii. The mold half I6 is constructed in amanner similar to that of the mold half i2, and water is introduced andwithdrawn from the jacket through conduits l4 and i5.

Hinging the machine i to enable it to bepositioned vertically, as shownin dot dash lines of Figure 5, greatly facilitates attaching the moldparts l2 and i6 thereto. These parts are, of necessity, bulky and heavyand difiiculty has been experienced in the past in properly aligningthem in proper register with one another;

By positioning the machine vertically and separating the bed plates 2and 3 by air pressure in the cylinder or otherwise, the mold part l2 maybe easily positioned on the plate 2 in its approximately correctposition. The part I6 is then be removed from th placed on top of thepart l2 where it will naturally register with this part due to the shapeof the parts, doweling or otherwise. Next the plate 3 is lowered intocontact with the mold and the parts are bolted to their respectiveplates before the machine is lowered to its horizontal operativeposition.

In order to impart longitudinal movement to the bed plate 3 and as aconsequence to the mold half i6, it will be seen that a spider I8 issuitably affixed to the movable bed plate 3. One end of a piston rod I9is detachably secured to the spider as shown at 20. The rod l9 extendsthrough a stuifing box 2| provided in the yoke 8 and into a cylinder 22bolted to the yoke 8 as at 23. The opposite end of the rod l9 supports apiston head 24 which reciprocates within the cylinder 22. The end of thecylinder 22 is closed by means of a cap 25 and gasket 26 will afford aleak-proof union between the cap and the cylinder.

In the present invention, the movable mold half I6 is adapted to bemoved into operative position with respect to the fixed mold half i3 byvirtue of the piston 24 and held thereagainst under pressure for apredetermined P riod of time to enable the molten material to be pouredinto the mold l3. Means are then adapted to move the movable mold partIS a short distance away from the fixed mold part after the metal hassolidified thereby eliminating deleterious strains due to shrinkage oncooling of the molten metal. The piston 24 is then moved to move themovable mold part l6 completely away from the fixed mold half l3 toenable the casting to be removed from the mold.

To release the movable mold part i6 immediately upon the expiration of apredetermined time interval from the fixed mold half, I provide a pairof release members 28. The release member 28 comprises a socket 29 thatis detachably secured to the guide rail 4 slightly forward of the fixedbed plate. Mounted within the socket is a helical spring 30, one end ofwhich bears against a threaded plug 3| that closes the end of thesocket. The other end of the coil spring 30 engages a plunger 32 whichprojects through an aperture 33 in the other end of the socket. A bolt34 havin a head 35 is threaded into the bore of the plunger 32. Thespring 30 will maintain the parts normally in the position shown inFigures 1 and 4. When the piston 24 moves the bed plate to the positionwhere the mold half I6 is in engagement with the mold half i3 for thepouring cycle, the guide members 5 carried by the movable bed plate willengage the bolt head 35 and compress the spring 30 to move the plungerto the position shown in Figure 3. However, as soon as the fluidpressure on the piston head 24 is released, the spring forces theplunger 33 and the bolt 35 toward the right thus cracking slightly themold parts l6 and I3 and enabling the casting to shrink freely withinthe mold cavity. Of course, by proper manipulation of the bolt 34 it ispossible to vary the amount of movement of the movable part away fromthe fixed part. This structure will eliminate undesirable strains whichwould be encountered during the shrinking of the molten metal if themold had not been cracked.

The control for operating the movement of the movable mold part withrespectto the fixed mold part i3 is accomplished by means of anelectrically operated valve control indicated generally 40. The valvecontrol 40 comprises a solenoid operated three way valve 4| and asolenoid controlled pneumatic operated four way valve 42.

As best shown in Figure 9, the valve 4| includes a body portion 43,inlet seat 44 and outlet seat 45. The seats 44 and 45 are adapted to beclosed by opposed spring loaded discs 46 and 47, respectively. The discs48 and 41 are operated by a lever 48 that is operatively connected at 48to a plunger of solenoid 5i mounted on the valve body 33.

The body is further provided with an inlet port E and an outlet port Fwhich communicates with the head end of cylinder 22 through a conduit52. Exhaust port G is also formed in the body 43.

The four way valve 42 comprises a body portion 42 and inlet port Athrough which fluid is introduced by pipe 52'. There is further providedan exhaust portB and an outlet port C which is connected to the-rod endof the cylinder 22 by means of a conduit 53. Mounted-within the valvebody it are opposed spring loaded discs 54 and 55 that close valve seats55 and 57, respectively, to control the flow of air to the pipe 53.Also, spring loaded discs 58 and 59 are adapted to seal seats 68 and ti,respectively, to control flow of air through port D to a pipe 53'connected with the inlet port E of the valve 4H. t

The discs 5d, 55, 58 and 59 are moved-by means of a mushroom head 53that is actuated by a flexible diaphragm Bil secured within the body42'.

The air which operates the diaphragm 84 is controlled by means of asolenoid valve 65 which is similar in construction and operation to thevalve ll This valve has ports b, d slide and port b is connected withport a on the pressure side of the four way valve througha conduit 66.The

port d is in communication with the port 0 on theexhaust side of thefour way valve through connection 68 and port 9 is connected to port fby means of a pipe 69.

The timing mechanism for operating the valve control fill and themovable mold part i6 is best shown in Figures 10 to 13 inclusive; Itcomprises a shaft it! which carries spaced segments ll, 12 and i8 and acollector ring i4. Rotary movement is imparted to the shaft 10 through aworm wheel '75 and a worm gear '78. Theworm gear 15 may be driven fromany suitable source of power such as a constant speed motor 16'. In thisparticular embodiment, the cycle of casting operations extends for aperiod of one minute and consequently I provide 60 segments that arespaced 30 apart. It will be appreciated therefore that each cycle ofoperation occurs at intervals of ten seconds. While the above length-andstagger of segments are used as an illustration other variations may beemployed to suit diiferent operating conditions.

asema'z The solenoids 5| and 85 are connected by lead lito one terminalof a source of electrical energy and the other terminal has a contactor18 which contacts collector ring 14. A signal light I9 is interposed inthe lead I? and is connected through line 80 witha contactor 8| thatmakes contact with the segment 7|. Solenoid 5| has a lead 82 whichterminates in contactor 83 adapted to make contact with segment 13 andsolenoid is also connected through a line 84 with a contactor 85 whichwill make contact with the seg-' ment '12.

In Figure 10 I have shown diagrammatically prise a double check valve.

. 3 inder through connection 52, port F, port E of the three way valve4|, port D, and out through exhaust port B in the four way valve. Atthis particular stage the solenoids 5| and 65 are deenergized and thesignal lamp 79 has just become lighted indicating a ten second intervalbefore the mold closes. The position orthe solenoid valves is that shownin Figure Upon the expiration of the ten second interval, the circuit tothe signal lamp 1! is still maintained through segment 1|, line 80 andline ll.

At the same time the circuit is completed to the solenoid 65, throughsegment 12, contactor 85, line 84 and back to the load line 17. At thistime the air entering the four way valve 42 leaves through port D,through pipe- 53 to port E in the valv 4|, out through port F into thehead end of the cylinder through pipe 52 to move the movabl mold partinto operative position with respect to the fixed mold part for thepouring operation. The air is exhausted from the rod end of the cylinderthrough line 53. port C in the valve 42 and out through the exhaust portB.

At the beginning of the third cycle, the circuit to the signal lamp isbroken as the segment 1| moves out of contact with contactor 8|indicating that the mold is' about to crack. Contactor 85 is still incontact with segment 12, thus keeping solenoid 85 energized. Thecontactor 83 now makes contact with segment 13 and the circuit tosolenoid 5| is completed, thereby energizing said solenoid. At this timeair pressure from the valve 42 is prevented from passing valve 4| andreaching the cylinder 22 by reason of the fact that the valve seat 44 ofthe valve 4| is closed. Exhaust port G of valve 4| is connected to portF as disc 41 is lifted from its seat 45. This allows free exhaust of theair in the head end of cylinder 22 through ports F and G of valve 4 I,thereby permitting free movement of the piston 24. Consequently therelease members 28 may now function to move the mold part l6 slightlyaway from the mold part |2 to permit the casting to shrink free of themold cavity.

At the beginning of the final cycle of operations, solenoid 5| isenergized and solenoid 65 becomes de-energized and the signal lamp isout. The air entering valve 42 through port A leaves through port Cthrough line 53 to the rod end of the cylinder to move the piston'headtoward the right as shown in Figure 13. The air at the head end of thecylinder is exhausted through conduit 52 through port F at the valve 4|and out through exhaust port G. During this cycle the movable mold partI6 is moved to its completely open position to permit the casting to beremoved from the mold.

Thetiming mechanism continues its operation and the cycles abovedescribed are again repeated and these cycles will continue to berepeated until the motor driving the worm wheel and worm gear 15 and 15,respectively, is stopped.

To control the rate of movement of the piston 24, speed control devicesmay be inserted in the air conduits 52 and 53. These speed controllersare designated 86 and 81, respectively, and com- Each valve is providedwith a port 88 to permit air to be admitted to the cylinder 22' and aport 89 to permit air to be exhausted therefrom. Each of these ports isadapted to be opened and closed by discs 90 and.

provide a dampening efleot for the movement of the piston.

It is thought apparent from the above description that I have provided acasting machine wherein a movable mold section is moved into operativeposition with respect to the fixed mold section for a predeterminedperiod of time to permit pouring of the molten metal into the mold.Immediately upon the expiration of a certain amount of time the movablemold part is moved slightly away from the fixed mold part to permit thecasting to shrink freely within the mold thereby preventing deleteriousstrains being imposed on the castings. After the casting has cooled, themovable mold section is moved completely away from the fixed moldsection to permit the casting to be removed from the mold.

The above cycle of operations is automatic and permits a multiplicity ofcastings to be cast within a minimum of time and with a minimum ofeffort on the part of the foundryman.

I claim:

1. In a permanent metal mold having a stationary mold block and amovable mold block adapted to be moved into engagement with thestationary block to close the mold and away from the stationary block toopen the mold, a reciprocable actuating device responsive todifferential in pressure on opposite sides thereof and operativelconnected with the movable block, valve means serving to apply fluidpressure on either of said actuating device and release pressure on theopposite side, additional valve means associated with the first valvemeans for controlling the application and release of pressure on oneside of said actuating device, and means for operating said valveswhereby fluid pressure is applied to one side of the actuating deviceand released from the opposite side to close the mold, thensimultaneously released from both sides to permit free movement of themovable block with respect to the stationary block and then applied tothe opposite side and released from the first mentioned side to open themold.

2. In a permanent metal mold having a stationary mold block and amovable mold block adapted to be moved into engagement with thestationary block to close the mold and away from the stationary block toopen the mold, a reciprocable actuating device responsive todiflerentialin pressure on opposite sides thereof and operatively connected with themovable block, valve means serving to apply fluid pressure on eitherside of said actuating device and release pressure on the opposite side,additional valve means associated with the first valve means forcontrolling the application and release of pressure on one side of saidactuating device, means for operating said valves whereby fluid pressureis applied to one side of the actuating device and released from theopposite side to close the mold, then simultaneously released from bothsides to permit free movement of the movable block with respect to thestationary block and then applied to the opposite side and released fromthe first mentioned side to open the mold, and spring means forseparating the movable block irom the stationary block during the periodof free movement of said movable block.

3. In a permanent metal mold having a stationary mold block and amovable mold block adapted to be moved into engagement with thestationary block to close the mold and away from the stationary block toopen the mold, a reciproca-ble actuating device responsive toditfcrential in pressure on opposite sides thereof and operativelyconnected with the movable block valve means serving to apply fluidpressure on either side of said actuating device and release pressure onthe opposite side, additional valve means associated with the firstvalve means for controlling the application and release 0! pressure onone side of said actuating device,

means for independently operating the valves, and a timing device forcontrolling the operation of said operating means to thereby applypressure to one side of the actuating device and release pressure fromthe opposite side to close the mold for a predetermined interval oftime, then release pressure simultaneously from both sides of theactuating device for a second predetermined interval of time and finallyapply pressure to the opposite side of the actuating device and releasepressure from the first mentioned side to open the mold.

- HENRY E. McWANE.

